The Belgium playmaker’s father Thierry told Belgian newspaper Le Soir that Hazard has had the injury for up to four months – it first occurred under Jose Mourinho, whom Hiddink replaced in December – but has had to play on.

“His father made a fair judgement. He is not absent of injury,” Hiddink said.

“What is an injury? You can have an injury where you cannot play, or where you can play when you are not fully fit.

“I have my concerns about him as well: whether he should play, when he’s not top, top fit, an hour at full intensity or another part of the game (as a substitute). We’re trying to help him.

“He will be available (against Everton). He’s desperate to participate in a team performance.”

Thierry Hazard told Le Soir his son’s injury is “not serious, but the pain, once it appears, is a stabbing pain”.

He added: “Instead of giving him time to rest and to cure totally, they need Eden to play, especially when it’s a very important match, and then to force him. He doesn’t have any choice.”

Hazard’s condition appears to be perplexing Hiddink, who spoke to Chelsea’s medical staff on Thursday and analysed statistics in the absence of “emotion”. The statistics from training and matches do not point to a problem, the Dutchman says.

Hiddink added: “I try to exclude a lot of emotion in that and see whether his working radius is okay. The intention he is doing in training and in the game, it’s not what you think. You think sometimes ‘oh, he’s not doing enough’. That’s not true.

“We have to find another entrance to get him on this level. Working harder is possible, but not with stupidity. Or maybe one or two days off might help.”

Hiddink discounted an extended leave, although that option is available now Chelsea are out of the Champions League.

He added: “I like to have (players) near to see what is best.”

Hazard senior conceded his son’s bad form came before the injury, saying “he’s not a machine”, while he also dismissed the prospect of a summer switch to PSG. Hazard is under contract at Stamford Bridge until 2020.

Hiddink added: “His father was very humble and made a very good comment about this. Some players have difficult times, although they are trying.

“Most of the time we have the idea ‘he’s not in big, big form, let’s try to punish’. Most of the players ask for a little bit of help.

“Every now and then I see that he (Hazard) is capable of doing beautiful things, very efficient things. We try to help him and find a path where he can grow and it’s a different approach for everyone.”

Striker Diego Costa is undergoing treatment for a hip problem which forced him off against PSG and is a doubt for the trip to Everton, but captain John Terry will return to contention after a six-match absence with a hamstring problem.

Hiddink said: “He worked rather well the past days. I would like him to travel to Liverpool.”

Terry scored an equaliser in the eighth minute of stoppage time to earn a 3-3 draw with Everton in January’s Premier League clash at Stamford Bridge.

The defender lifted the FA Cup in 2009 during Hiddink’s first caretaker spell as manager and the Blues boss is eager for further success in the competition, but not at expense of climbing further up the Premier League table from 10th position.

“It’s a very important cup to go for,” Hiddink said. “But you have to focus also on the Premier League and not neglect that.”